This description relates to optical logical components, and, more particularly, to systems and methods of forming components using parity-time symmetry and it's breaking, exhibiting non-linearity-based nonreciprocal light transmission using parity-time symmetry.
A challenge in the field of photonics is developing new materials and devices with unconventional and advanced functionalities to control the flow of light on-chip. Recently, optical systems combining balanced loss and gain have been proposed to originate synthetic materials with properties that cannot be attained in materials having only loss or only gain. Such systems provide a platform to implement classical analogues of quantum systems described by non-Hermitian parity-time (PT) symmetric Hamiltonians and are expected to play a significant role in optics. PT synthetic materials utilize modulation of the coupling strength between individual molecular or macroscopic sub-components and sub-systems of a larger system, its refractive index, and gain and/or loss. This leads to phenomena such as asymmetric power oscillations between two waveguides (sub-systems of larger sub-systems) and unidirectional reflectionless light propagation. Parity-time symmetry can be obtained when using a pair of coupled systems (e.g., coupled waveguides and/or coupled resonators) with one dissipating light-waves while the other is amplifying an equal amount. The optical power in the gain system (i.e., active system, such as an active waveguide) can increase while optical power decays in the other. The propagation of light is non-reciprocal in that the power oscillation between the two coupled sub-systems is no longer symmetric. However, the transmission remains reciprocal. Loss-induced transparency, power oscillations violating left-right symmetry, PT-synthetic photonic lattices, and unidirectional invisibility have been demonstrated, but other phenomena such as nonreciprocal light transmission, prior the technology as disclosed herein; and coexisting coherent-perfect-absorption (CPA) and lasing are yet to be realized. These could benefit significantly from resonance structures exhibiting PT-symmetry. However, to date, experiments in PT-symmetric optics have been limited to waveguides in which resonances play no role.